I prefer VimScript over Lua. VimScript is really not that bad of a language and I think its deficiencies have been greatly exaggerated, and Vim9Script fixed most of the oddities that were in there (e.g. '1' == 1 and such, JS/PHP-style).
Lua, on the other hand, won't give me an error if I mistype a variable name, and the ecosystem doesn't really have good static analysis tools to catch these kind of silly errors. There's some other things I don't like either, like how "arrays" are really just hashmaps, as well as some other things. The whole versioning story wrt. compatibility is also annoying (it's basically a Python 2/3 story with every single Lua version).
It's not Lua is horrible, but the fawning over it from some Neovim people is something I always found curious, like it's a fantastic brilliant language. Meh, I found it quite average overall, at best. And if I look at some Lua vimrcs or plugins then it's all a lot more verbose and awkward than VimScript.
Not that VimScript is perfect by any means, but overall I find it's quite a decent DSL for an editor.
Fair, though neovim uses LuaJIT which is maintaining Lua 5.1 compatibility indefinitely; with their own set of extensions[1].
Through the use of metatables you can improve the undeclared global situation[2], through I admit it's kludgy.
We use luacheck for static analysis, but I'll admit it's far from perfect. The language doesn't lend itself well to static analysis.
I think what lua mostly has is a really good embedding story. It's a tiny C library with broad compatibility and a permissive license; and with LuaJIT it's also very fast (though less portable). This means it's used everywhere and a lot of people are at least passingly familiar with it. Vimscript on the other hand is fairly alien.
I feel the same way. Legacy vimscript certainly had some warts but vim9script has been much nicer IME than lua. Elsewhere I've likened vim9script to typescript 1.0. It has just enough types to be useful but not enough to let you go down a rabbit hole. That's sort of the sweet spot when scripting another application.
:shock: